An integrated circuit may employ numerous types of transistors. In order to obtain highly integrated devices, the size of integrated circuits has gradually decreased. Accordingly, there may also be a need to gradually reduce the size of transistors.
As illustrated in example FIG. 1, a 2-input NOR gate circuit may include first PMOS transistor P1 and first NMOS transistor N1, which share a first gate connected to first input I/P A, and second PMOS transistor P2 and second NMOS transistor N2, which share a second gate connected to second input I/P B.
A first source/drain junction of first PMOS transistor P1 may be connected to output line O/P. A first source/drain junction of second PMOS transistor P2 may be connected to power supply line Vdd. First PMOS transistor P1 and second PMOS transistor P2 may have second source/drain junctions connected to each other. The first source/drain junctions of first NMOS transistor N1 and second NMOS transistor N2 may be commonly connected to output line O/P. The second source/drain junctions of first NMOS transistor N1 and second NMOS transistor N2 may be commonly connected to ground supply line Vss.
Because such a NOR gate circuit may be structured to include two PMOS transistors and two NMOS transistors, achieving high integration is may be problematic.